Cowbirds lay their eggs in neighboring nests and abandon the to be raised by surrogate bird parents. Researchers recently spent some attempting to figure out whether the birds know they are different from their adopted families and how they handle it in terms of feeding, mating and flocking.
Eurasian cuckoos, one of which is pictured here, are invading North America. Climate change has taken its toll on the Bering Strait's landscapes, which has made it easy for these birds to migrate to new lands. However, this could cause drastic declines of native bird populations.